Change 'Open Textbook Builder' to 'Open Textbook Planner'
Expected behaviour
It should be 'Open Textbook Planner' everywhere.
Current behaviour
When you click 'Build book' at the end of the planner steps, it says 'Open Textbook Builder' in the text in the modal that appears:
Steps to reproduce
- Go to the OEN instance
- Add a book and plan the book
- Go to step 4 and then click 'Build book'
- See the text in the modal that appears says 'Open Textbook Builder' instead of 'Open Textbook Planner' (it should be the latter)